packet.

connection was recognised.

plugin.

connection once.

Runnables encapsulating database or IO tasks are passed to the
relevant threads. The IO thread's task queue is unbounded to avoid
deadlock, but its growth is indirectly limited by the progress of
database tasks.

This will enable asynchronous access to the database for IO threads.

memory.

This ensures the frame number is covered by the MAC, cleanly
separating encryption from authentication (previously we depended on
the encryption layer to garble frames if they were reordered).